There are a number of new features rolling out today, including larger file transfers, and larger groups.
Evidence of their development first came to light last summer, and for some time has been working on message reactions.
The feature allows users to respond to a message with a thumbs-up or thumbs-down without having to type out a lengthy reply in the chat thread.
Similar to Facebook Messenger, users of the messaging service will soon see a row of symbols. All emojis and skin-tones will be added in the future, but at the moment only a few common reactions are available.
There is a larger cap on file transfers between users of the instant messaging platform. The file-sharing capabilities have become a key feature of the service, and the app has included the ability to share media files within conversations, but its 100MB file size limitation hasn't changed in that time.
The platform will be more open to sharing video clips and other large media file types if the limit is raised to 2GB.
From today, the default size of group chats will be expanded to 512 users, up from the previous limit of 256. The larger group limit is being rolled out slowly, while the larger file size transfer limits should be available in the current version of the app.